666365560 has 128 divisors (see below), whose sum is σ = 1776867840. Its totient is φ = 220147200.

The previous prime is 666365533. The next prime is 666365561. The reversal of 666365560 is 65563666.

It is a happy number.

It is a super-2 number, since 2×666365560² = 888086119108227200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666365561) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1356915 + ... + 1357405.

It is an arithmetic number, because the mean of its divisors is an integer number (13881780).

Almost surely, 2^666365560 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666365560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (888433920).

666365560 is an abundant number, since it is smaller than the sum of its proper divisors (1110502280).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

666365560 is a wasteful number, since it uses less digits than its factorization.

666365560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 677 (or 673 counting only the distinct ones).

The product of its (nonzero) digits is 583200, while the sum is 43.

The square root of 666365560 is about 25814.0574106435. The cubic root of 666365560 is about 873.4489244796.

The spelling of 666365560 in words is "six hundred sixty-six million, three hundred sixty-five thousand, five hundred sixty".